It reminds me of "hidari mae" - the wearing of the uwagi with the left side on top of the right, which, as you probably know, is only done once in your life, and that is the last time - unless you are a poor unsuspecting newbie from outside Yamato.

There is a story of a foreign woman being carried out of the Yoshinkan Hombu because she inadvertently had put on her uwagi hidari mae, but this is off-topic.

I think you have it backwards. The kimono and uwagi are worn with the left side over (outside of) the right, until death, despite the literal meaning of hidarimae:

"When the kimono shroud was completed, the body of the deceased was carefully dressed with the right front overlapping the left front, which is known as the hidarimae manner. (Normally, a kimono is worn with the left front panel overlapping the right front panel.) In ancient times the Japanese had worn their kimono the hidarimae way. But this custom began to change in the seventh century, when Chinese court costumes were introduced. Because the Chinese wore their costumes overlapped in the opposite direction, there was a period of confusion: some Japanese held to the old way; some adopted the Chinese way. Finally, in the eighth century, Emperor Gensho (715-723) instituted a dress code that required the Japanese to wear their kimono with the left front over the right. After that, wearing a kimono hidarimae was avoided in Japan; it was considered an omen of misfortune or even death. The issei immigrants to Hawaii of course brought these beliefs with them. Issei mothers would reprimand their children for inadvertently wearing their bedtime kimono overlapped the wrong way, and mothers would become especially upset if their daughters wore their kimono in the hidarimae manner on New Year's Day, since that might mean that the whole year would be unlucky. A plantation mother might say, "You wearing make man style?" (Make means dead in Hawaiian.) To this day, when issei women see people of other ethnic groups at Obon dances or teahouse parties wearing kimono the hidarimae way, they have the same reaction: they feel it is a bad omen. The younger-generation Japanese probably do not even notice."